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In this work, the microwave-assisted synthesis of manganese metal–organic framework (MOF) material is presented. Synthesis procedure is based on a microwave-assisted solvothermal reaction of manganese(III) acetylacetonate with biphenyl-4,4′-dicarboxylic acid (Bpdc) in N,N′-dimethylformamide at the temperature of 160 °C. The obtained Mn-based metal–organic framework, labeled as Mn-Bpdc, was used as a precursor for the preparation of a porous MnO/carbon nanocomposite, which was obtained via thermal transformation in a nitrogen atmosphere at 700 °C. It was found that this approach provides an effective and simple preparation pathway for porous carbon decorated with homogeneously embedded manganese(II) oxide nanoparticles. Both Mn-Bpdc and MnO/C nanocomposite materials were characterized by a variety of physicochemical methods. The prepared MnO/C nanocomposite material was deposited on a cathode surface of lithium-sulfur batteries and utilized as a shuttle suppressing layer. This electrode structure immobilizes polysulfides inside the cathode and improves the stability during cycling. The electrode with MnO/C nanocomposite shuttle suppressing layer maintains high stability during cycling in comparison with a standard electrode. The electrode with MnO/C composite layer exhibits 84.8% capacity retention after 50 cycles at different C-rates compared to 76.2% obtained for the standard electrode. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Original facile microwave-assisted synthesis of Zinc oxide nanoparticles is reported. • Prepared ZnO nanoparticles form stable colloidal dispersions in toluene. • Solution of MEH-PPV polymer and ZnO nanodispersions mix without agglomeration. • Polymer LEDs with MEH-PPV/ZnO nanocomposite active layer were successfully prepared. • The PLEDs with MEH-PPV/ZnO layer exhibited high electroluminescence at low voltage. Abstract Zinc oxide nanoparticles were synthesized via microwave-assisted reactions from a zinc acetate dihydrate. The reactions were performed in diethylene glycol (DEG) at 220 °C and 250 °C while using oleic acid as the surfactant. The ZnO precipitates obtained were washed with methanol and dried or kept as colloidal solutions redispersed in toluene. The size of the nanoparticles ranged from ca. 5 to 12 nm and they could be modified by the concentration of Zn precursor. Different morphologies due to the function of oleic acid concentration were observed. The resulting ZnO nanocolloids were mixed with the poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) polymer to obtain MEH-PPV/ZnO nanocomposites. The nanocomposite layers exhibited optoelectronic properties which were found to be beneficial for being applied as the active layer in the polymer light emitting diodes. The intensity of the electroluminescence of the prepared PLED devices was enhanced by one order of magnitude keeping all other parameters constant and powered as the same operation voltage. As additional step the effect of active layer thickness on optoelectronic performance of PLED devices was investigated as well. [ABSTRACT FROM AUTHOR]

Abstract Co x Zn 1-x O (x = 0.01, 0.05 and 0.1) nanoparticles were prepared by microwave-assisted polyol method from zinc acetate dihydrate and Co(II) acetylacetonate. The reactions were performed in diethylene glycol (DEG) at 250 °C with the use of oleic acid as a surfactant. Resulting nanoparticle (ca. 10 nm) precipitates were washed with methanol and dried or kept as colloidal solutions redispersed in toluene. Colloidal solutions were mixed with the Poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) polymer to produce thin nanocomposite layers with specific optoelectronic properties. The electronic structure in terms of density of states (DOS) of MEH-PPV and MEH-PPV/nanocomposite layers was investigated by recently proposed energy resolved electrochemical impedance spectroscopy method. The MEH-PPV polymer and its nanocomposites with ZnO or Co x Zn 1-x O nanoparticles were used as thin active layers in polymer light emitting diodes (PLED). The nanocomposite layers exhibited optoelectronic properties which were found to be beneficial as the active layer in PLEDs, exhibiting an order of magnitude enhancement in electroluminescence intensity. A pronounced effect on the opening bias voltage of final devices with Co x Zn 1-x O nanoparticles was also observed. Graphical abstract Image 1 Highlights • Original facile microwave-assisted synthesis of Co x Zn 1-x O nanocolloids is reported. • Solution of MEH-PPV polymer and Co x Zn 1-x O nanodispersions mix without precipitation. • MEH-PPV/Co x Zn 1-x O composite layers electronic structure mapping by ER-EIS technique. • PLEDs with MEH-PPV/Co x Zn 1-x O nanocomposite active layer were successfully prepared. • The PLEDs with MEH-PPV/Co x Zn 1-x O layer exhibited lowering of opening bias voltage. [ABSTRACT FROM AUTHOR]

This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described. [ABSTRACT FROM AUTHOR]

Non-hydrolytic sol–gel reactions of silicon acetates with trimethylsilyl (TMS) esters of phosphoric and phosphonic acids produce cross-linked matrices containing homogeneous dispersions of silicate and phosphoryl groups connected together by networks of Si–O–P(=O) linkages. The condensation degrees reach 80 to 90%. Residual organic groups (10 to 20%) were reacted with a variety of compounds (H2O, Me3SiOSiMe3, POCl3, SiCl4, AlMe3, Al(NMe2)3, and AlCl3) in order to enrich the surface of these porous matrices with Brønsted (≡P–OH) and Lewis (tetracoordinated Al) acid functional groups. The differences in the reactivity of ≡Si–OAc and ≡P–OSiMe3 groups were utilized for the selective modification at the silicon and phosphorus atoms. The reaction procedures were optimized and significantly porous silicophosphate materials with a high content of either hydroxyl groups or four-coordinated aluminium species were obtained. The activity and selectivity of prepared samples as catalysts for the dimerization of α-methylstyrene were tested. Excellent activities and moderate to very high selectivities were achieved suggesting the potential use of silicophosphate xerogels in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

A novel non-hydrolytic sol-gel (NHSG) synthesis of mesoporous zirconium silicate xerogels is presented. The condensation between silicon acetate, Si(OAc), and Zr(NEt) resulting in acetamide elimination leads to homogeneous zirconium silicate xerogels containing Si-O-Zr linkages. The addition of Pluronic P123 template provides stiff gels that are after template removal by calcination at 500 °C in air converted to stable mesoporous xerogels with wormhole-type pores, high surface area over 500 m g, and tetrahedrally coordinated Zr atoms in the framework. The composition and morphology of the xerogels, volatile reaction byproducts, and thermal transformations were followed by elemental analysis, IR spectroscopy, thermal analysis TG-DSC, nitrogen adsorption, C and Si solid-state NMR spectroscopy, DRUV-Vis spectroscopy, SAXS, and HT powder XRD. These potential catalysts were tested for the Meerwein-Ponndorf-Verley reduction of 4- tert-butylcyclohexanone and for aminolysis of styrene oxide with aniline. Resulting reaction systems display good activity and selectivity. [ABSTRACT FROM AUTHOR]

In this work, vanadium metal-organic framework derived VO x /carbon and VO x /N-doped carbon nanocomposites are presented. The methodology introduced here is based on a novel polyol synthesis of vanadium metal-organic frameworks (MOFs) involving a microwave-assisted solvothermal reaction of vanadyl acetylacetonate with biphenyl-4,4′-dicarboxylic acid (Bpdc) and/or 2,2′-bipyridine-4,4′-dicarboxylic acid (NBpdc) in diethylene glycol (DEG) at the temperature of 230 °C. The V-based MOFs, labeled as V-Bpdc and V-NBpdc, were used as precursors for the preparation of VO x /carbon and VO x /N-doped carbon nanocomposites with unique sponge-like nano-sheet and paperclip-like morphology, respectively. The nanocomposites were obtained via thermal transformation of as-prepared vanadium MOFs in the argon atmosphere at 600 °C. The VO x /carbon sample consists of nano-sheets with the thickness 5–20 nm while the VO x /N-doped carbon paperclip-like nanocomposite has a rod diameter 35–70 nm. It was found that the approach reported here provides an effective and simple preparation pathway of carbon-based nanocomposites containing homogeneously distributed VO x species. Both V-MOFs and V-MOF-derived nanocomposites were characterized by the variety of physicochemical methods. In the following step, the obtained nanocomposites were investigated as electrode materials in sodium-ion batteries. Based on the obtained results, high electrochemical activities of VO x /carbon and VO x /N-doped carbon nanocomposites were evidenced. Particularly, in the case of VO x /N-doped carbon-based electrode, high capacity and low irreversible capacity were achieved. Therefore, reported materials are found to be promising candidates for electrode materials in sodium-ion batteries. [Display omitted] • Novel microwave-assisted polyol synthesis of vanadium MOF materials introduced. • Original nano-sheet and paperclip morphologies of V-MOF derived nanocomposites. • VO x /Carbon and VO x /nitrogen-doped carbon successfully utilized in Na-ion batteries. • Improved electrochemical behavior of VO x /N-doped carbon due to nitrogen doping. • Low irreversible capacity and high performance V-MOF derived nanocomposites observed. [ABSTRACT FROM AUTHOR]

Room temperature phosphorescence carbon dots (RTP CDs) are one of the newly investigated nanomaterials because of their remarkable optical characteristics. They are widely utilized in many versatile optoelectronic and security applications. Apart from synthesis, one of its challenging attributes is its lifetime at room temperature. Here, a straightforward and quick heating approach is presented for synthesizing self‐matrix 1,10 phenanthroline and boron‐based RTP CDs. 1,10 phenanthroline is utilized as an aromatic and hetero atom containing carbon precursor and boric acid is used as a passivating to stabilize the triplet excitons and prevent nonradiative deactivation. Various characterization techniques like TEM, XRD, FTIR, UV–vis, PL, and elemental analysis (ICP and CHNS) have been used to study the properties of self‐matrix RTP CDs. The RTP CDs exhibited excellent blue‐green emission when excited at 302 nm. Compared to the available literature, the novelty of this work is observed from its high naked eye phosphorescence characteristic of ≈22 s with an average lifetime of ≈ 2.4 s at 302 nm, making them ultralong self‐matrix RTP CD material. Due to their exceptional qualities, the self‐matrix RTP CDs have been widely employed for various applications, including information encryption decryption, phosphor for LEDs, anticounterfeiting, and water sensitivity analysis. [ABSTRACT FROM AUTHOR]

In this study, cellulose was carbonized in two-steps using hydrothermal and thermal carbonization in sequence, leading to a novel carbonaceous material prepared from a renewable source using a sustainable method without any chemicals and, moreover, giving high yields after a treatment at 600 °C in an inert atmosphere. During this treatment, cellulose was transformed to uniform microspheres with increased specific surface area and, more importantly, conductivity increased by about 7 orders of magnitude. The successful transition of cellulose to conducting carbonaceous microspheres was confirmed through SEM, FTIR, X-ray diffraction and Raman spectroscopy. Prepared samples were further used as a dispersed phase in electrorheological fluids, exhibiting outstanding electrorheological effects with yield stress over 100 Pa at an electric field strength 1.5 kV mm−1 and a particle concentration of only 5 wt%, significantly overcoming recent state-of-the-art findings. Impedance spectroscopy analysis showed clear interfacial polarization of this ER fluid with high dielectric relaxation strength and short relaxation time, which corresponded to increased conductivity of the particles when compared to pure cellulose. These novel carbonaceous particles prepared from renewable cellulose have further potential to be utilized in many other applications that demand conducting carbonaceous structures with high specific surface area (adsorption, catalyst, filtration, energy storage). [ABSTRACT FROM AUTHOR]

Microwave assisted heating was successfully employed in significantly accelerated preparation of expanded g-C 3 N 4 via thermal condensation of urea. Comparing to typical synthesis route, rapid microwave assisted heating enables not only shorten synthesis time from hours to few minutes but obtain reasonable yield of the product also. Use of ceramic kiln “hotpot” with intern covered with absorbing layer plays the key role in transformation of the microwave energy into heat. Heat energy in form of radiation from the glowing inner layer surface is focused into the internal volume of the kiln resulting in extremely fast temperature increase. Thus, microwave non-absorbing starting material is extremely fast heated. The effects of reaction conditions on the structural, morphological, optical and photocatalytic properties of prepared g-C 3 N 4 were investigated in detail. Having similar specific surface area but much larger particles than its conventionally prepared analogue, the microwave prepared material can be classified as expanded g-C 3 N 4 . Moreover, by simply changing the reaction time, photoluminescence emission of the material can be continuously tuned covering the blue to green light region of visible light. The photocatalytic degradation of Methyl Violet 2B reveal that the adsorption capacity of samples increases with processing time while the rate constant slightly decreases. It can be ascribed to the expansion of the internal surface which results in its worse availability to the diffusion transport of the dye to active sites. It also impedes photodegradation products removal. The synthesis technique described here could be considered applicable to starting materials, which cannot be sufficiently heated by microwave absorption directly. [ABSTRACT FROM AUTHOR]

A wearable and stretchable strain sensor with a gauge factor above 23 was prepared using a simple and effective technique. Conducting nanocomposite strands were prepared from styrene-b-(ethylene-co-butylene)-b-styrene triblock copolymer (SEBS) and carbon black (CB) through a solvent-processing method that uses a syringe pump. This novel nanocomposite preparation technique is a straightforward and cost-effective process and is reported in the literature for the first time. The work included two stages: the flexible nanocomposite preparation stage and the piezoresistive sensor stage. Depending on its molecular structure, the thermoelastic polymer SEBS is highly resilient to stress and strain. The main aim of this work is to fabricate a highly flexible and piezoresistive nanocomposite fibre/strand. Among the prepared composites, a composite corresponding to a composition just above the percolation threshold was selected to prepare the strain sensor, which exhibited good flexibility and conductivity and a large piezoresistive effect that was linearly dependent on the applied strain. The prepared nanocomposite sensor was stitched onto a sports T-shirt. Commercially available knee and elbow sleeves were also purchased, and the nanocomposite SEBS/CB strands were sewn separately on the two sleeves. The results showed a high sensitivity of the sensing element in the case of breathing activity (normal breathing, a 35% change, and deep breathing at 135%, respectively). In the case of knee and elbow movements, simultaneous measurements were performed and found that the sensor was able to detect movement cycles during walking. [ABSTRACT FROM AUTHOR]

The open porosity and number of Lewis acid sites in metal silicates (M = Zr, Ta) have been reported as key factors enabling reaching high butadiene (BD) productivity from ethanol. However, some microporous zeolites recently displayed very high BD yields. To gain a deeper insight, we have applied non-hydrolytic sol-gel (NHSG) in the preparation of micro-mesoporous zirconosilicates. The porosity, structure, and acidity of these materials have been described and compared to a benchmark sample prepared by dry impregnation. The detailed characterization proved that NHSG preparation provided highly homogeneous Zr dispersion in silica leading to almost doubled Lewis acid site numbers and higher activity in ethanol-acetaldehyde conversion to BD, Meerwein-Ponndorf-Verley (MPV) reaction, and aldol condensation, in comparison to the catalyst prepared by dry impregnation. The selectivity and stability were similar for catalysts prepared by NHSG and dry impregnation. [Display omitted] • Micro-mesoporous zirconosilicates synthesized by non-hydrolytic sol-gel (NHSG). • Micropore content controlled by the reaction conditions. • Better Zr dispersion in NHSG-prepared materials in comparison to a benchmark catalyst synthesized by dry impregnation. • Number of Lewis acid sites in NHSG-zirconosilicates reached up to double the number in material prepared by dry impregnation. • Activity in ethanol-acetaldehyde conversion to 1,3-butadiene and related reactions followed the Lewis acid site numbers. [ABSTRACT FROM AUTHOR]

Orthorhombic niobium pentoxide (T-Nb2O5) possesses an intercalation pseudocapacitive behavior, which is a promising candidate of high-rate anodes for Li-ion capacitors. However, its low electric conductivity hinders the realization of this property. In our study, niobium oxides/carbon composites were prepared by calcinating a niobium peroxo-PAA complex (NbPAA) precursor to improve the electric conductivity. It has been found that the calcination temperature played an important role on the chemical compositions of obtained composites. A reduction phenomenon of niobium oxides by carbon was observed at high temperatures. At the medium temperature of 900 °C, the sample was composed of T-Nb2O5, monoclinic Nb2O5 (M-Nb2O5), amorphous carbon and niobium dioxide (NbO2). Due to the high conductivity of carbon, semi-conductivity of NbO2, and high specific capacity of M-Nb2O5, this sample exhibits a good specific capacity of 142 mAh g−1 (0.25 C) and a high-rate capability (capacity retention of 33.1%, 0.25 C to 25 C). It could be used as one of high-rate anodes for Li-ion capacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel method (energy resolved-electrochemical impedance spectroscopy) for the characterization of the electronic structure of nanocomposite thin film, which serves as an active layer in prepared PLEDs, is used. • Two kinds of nanoparticle addition effects were investigated. • (A) Non-specific modification of the polymer chain packing ordering results into polymer electronic structure alteration. • (B) Specific roles connected with the electronic structure of the particles, their conductivity and doping contribution to the electronic structure of the emissive layer. The work is focused on power efficiency and luminance of polymer light-emitting diodes (PLED) based on polymer matrix and nanoparticulate filler. As polymer matrices poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) were used. Nanofillers, aluminium-doped ZnO nanoparticles, were prepared by microwave-assisted polyol method and characterized by XRD, SEM, and TEM. Obtained nanoparticle colloids were mixed with dissolved polymer. Then, nanocomposite active layers of prepared PLEDs were spin-cast in one processing step. Specific optoelectronic and electric properties of nanocomposite materials and performance of PLED devices were investigated using UV–Vis absorption, photoluminescence, energy-resolved electrochemical impedance spectroscopy (ER-EIS), and I-V and luminance measurements. The addition of Al-doped ZnO nanoparticles improved power efficiency of diodes exhibiting an order of magnitude enhancement in electroluminescence intensity, luminance (from 1 900 to 20 700 cd/m2 for MEH-PPV and from 4 600 to 38 000 cd/m2 for F8BT) and had pronounced effect on opening bias voltage of final devices. In addition, two effects of nanoparticulate doping were revealed. The first, specific one, related with electronic structure of used nanoparticles. The second, non-specific, which indirectly contributes to structural ordering of the polymer matrix. Observed phenomena are related to electronic band structure affected by the addition of nanoparticles as revealed by ER-EIS. [ABSTRACT FROM AUTHOR]

This work describes the preparation of a novel biopolymer hydrogel based on acid whey, cellulose derivatives and polyvinyl alcohol (PVA). The hydrogel was prepared and characterized with the aim of producing an environmentally-friendly soil amendment to increase water retention capacity of the soil. The findings showed considerable swelling properties of the hydrogels depending on the PVA content and crosslinking density. The samples with PVA in a concentration 2.5 % and 5 % were more rigid, the gel fraction increased with a subsequently decrease in their swelling capacity. The hydrogels crosslinked with 15 % of citric acid demonstrated a constant swelling ratio (SR) of around 500 % within 10 swelling/drying cycles. The hydrogels crosslinked with 10 % citric acid and supplemented with 1 % of PVA showed SR of 1000–1400 % caused by less crosslinked polymer network and increased pore volume for water uptake. It was found that hydrogel with a higher gel fraction had a stable structure. Supplementing PVA at 5 % extended the period of decomposition of the hydrogel material by almost 60 % in the soil environment and soil humidity was maintained for longer. Applying 2 % of the hydrogel 5PVA to soil increased the water retention capacity by 19 %. • An environmentally-friendly soil conditioner was prepared for sustainable agricultural applications. • The effect of polyvinyl alcohol on the swelling properties and biodegradability of the hydrogels was evaluated. • Addition of 5 % PVA extended the period of biodegradation of the hydrogel in soil by almost 60 %. • The results show the potential of acid whey to be a source of nutritive whey agents for plants. [ABSTRACT FROM AUTHOR]

This study explores the structural and electrical properties of sodium carboxymethyl cellulose (NaCMC)–pectin (PC)–glycerol–NH 4 Br electrolyte films and investigates their potential applications in proton batteries. Plasticized solid polymer electrolyte (SPEs) films were fabricated using the solution casting method. The interaction between the salt and polymer blends was verified using Fourier-transform infrared (FTIR) analysis. Incorporation of various salt concentrations (up to 25 wt%) was found to enhance the amorphous phase of the polymer blend, as evidenced by X-ray diffraction (XRD) results. Additionally, the decrease in the glass transition temperature, as confirmed by DSC analysis, indicates that the inclusion of both plasticizer and salt contributed to this effect. An electrolyte with 25% wt. of NH 4 Br has the highest room temperature conductivity of 4.68 × 10−4 S cm−1. This electrolyte was employed to fabricate the proton battery for energy storage application. [Display omitted] • Plasticized PC/NaCMC-NH 4 Br has been successfully synthesized. • Plasticized PC/NaCMC-NH 4 Br SPE shows ionic conductivity of 4.68 × 10-4 (S cm-1) along with an LSV up to 2.4 V. • The plasticized PC/NaCMC-NH 4 Br sample with the highest conductivity exhibits a low crystallinity index (χ %) of 11.98. • Transport properties through Nyquist plot fitting aligned with ionic conductivity trend. • The proton battery with 25 wt% of salt concentration demonstrates an OCV of 1.2. [ABSTRACT FROM AUTHOR]

Abstract This paper demonstrates a three-dimensional electromagnetic interference shielding nanocomposite flexible sheet which is consisted of NiFe 2 O 4 spinel ferrite nanoparticles, and carbon source materials such as graphite, graphene oxide and reduced graphene oxide in the elastomer matrix. The prepared nanocomposite exhibited ferromagnetic behavior. The total shielding effectiveness was up to 28.5 dB for the elastomer nanocomposite sheet having filler NiFe 2 O 4 nanoparticles with reduced graphene oxide. The coexistence of electric and magnetic dipoles in the prepared shielding nanocomposite sheet can response highly to electromagnetic waves and consequently high electromagnetic loss. The high value of shielding efficiency is also related to dual interfaces of NiFe 2 O 4 and reduced graphene oxide in the ternary NiFe 2 O 4 -Reduced Graphene Oxide-Elastomer nanocomposite. The investigated results indicate that the absorption attenuation is a dominant mechanism for electromagnetic interference shielding. The current study demonstrates a facile strategy to develop advanced lightweight electromagnetic interference shielding nanocomposite flexible sheet. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

In this work, a facile and green method for gadolinium doped cobalt ferrite (CoFe 2−x Gd x O 4 ; x = 0.00, 0.05, 0.10, 0.15, 0.20) nanoparticles by using ultrasonic irradiation was reported. The impact of Gd 3+ substitution on the structural, magnetic, dielectric and electrical properties of cobalt ferrite nanoparticles was evaluated. The sonochemically synthesized spinel ferrite nanoparticles were characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). X-ray diffraction (XRD) study confirmed the formation of single phase spinel ferrite of CoFe 2−x Gd x O 4 nanoparticles. XRD results also revealed that ultrasonic irradiation seems to be favourable to achieve highly crystalline single crystal phase gadolinium doped cobalt ferrite nanoparticles without any post annealing process. Fourier Transform Infrared and Raman Spectra confirmed the formation of spinel ferrite crystal structure. X-ray photoelectron spectroscopy revealed the impact of Gd 3+ substitution in CoFe 2 O 4 nanoparticles on cation distribution at the tetrahedral and octahedral site in spinel ferrite crystal system. The electrical properties showed that the Gd 3+ doped cobalt ferrite (CoFe 2−x Gd x O 4 ; x = 0.20) exhibit enhanced dielectric constant (277 at 100 Hz) and ac conductivity (20.2 × 10 −9 S/cm at 100 Hz). The modulus spectroscopy demonstrated the impact of Gd 3+ substitution in cobalt ferrite nanoparticles on grain boundary relaxation time, capacitance and resistance. Magnetic property measurement revealed that the coercivity decreases with Gd 3+ substitution from 234.32 Oe (x = 0.00) to 12.60 Oe (x = 0.05) and further increases from 12.60 Oe (x = 0.05) to 68.62 Oe (x = 0.20). Moreover, saturation magnetization decreases with Gd 3+ substitution from 40.19 emu/g (x = 0.00) to 21.58 emu/g (x = 0.20). This work demonstrates that the grain size and cation distribution in Gd 3+ doped cobalt ferrite nanoparticles synthesized by sonochemical method, is effective in controlling the structural, magnetic, and electrical properties, and can be find very promising applications. [ABSTRACT FROM AUTHOR]

Composite materials based on PLA have been studied in depth for many applications, including food packaging. This manuscript describes extensive research conducted on a biodegradable polymer (PLA), inorganic filler (CaCO 3), and polyester-based plasticizer (PEP, based on a copolymer of low-molecular-weight PLA and PEG) prepared under semi-industrial conditions, as applicable for the packaging of hot food. The properties of the composite were achieved by post-processing annealing, notably its thermal stability, thereby permitting contact of the material with hot food. The manner of processing was deemed suitable for deployment at an industrial scale, moreover, the thermal stability of the final product endured, evidencing its applicability for such packaging. Change in the morphology of the structure of the composite material depended on the composition and annealing process, as detailed herein. The effect of the post-production thermal annealing on the molecular weight of samples was studied using the gel permeation chromatography. The thermal properties of the composites were investigated by differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The crystallinity was assessed using X-ray diffraction technique, while mechanical behavior was tested in relation to the given tensile properties, shape stability at high temperature, and permeability by the transmission rates of gas/water vapor. [Display omitted] • PLA composite with CaCO 3 and plasticizer was prepared under semi-industrial conditions with a post-processing annealing. • The properties of the composite depended on the morphology and volume fractions of the crystalline and amorphous regions. • The two additive components and given technological conditions lends shape stability to the composite. • The composite was suitable for contact with hot food or use as packaging for foodstuffs that are heated in microwave ovens. [ABSTRACT FROM AUTHOR]

Ideally hexagonally ordered TiO2 nanotube layers were produced through the optimized anodization of Ti substrates. The Ti substrates were firstly covered with a TiN protecting layer prepared through atomic layer deposition (ALD). Pre-texturing of the TiN-protected Ti substrate on an area of 20×20 μm2 was carried out by focused ion beam (FIB) milling, yielding uniform nanoholes with a hexagonal arrangement throughout the TiN layer with three different interpore distances. The subsequent anodic nanotube growth using ethylene-glycol-based electrolyte followed the pre-textured nanoholes, resulting in perfectly ordered nanotube layers (resembling honeycomb porous anodic alumina) without any point defects and with a thickness of approximately 2 μm over the whole area of the pattern. [ABSTRACT FROM AUTHOR]

Abstract: The Cu–Ni nanoalloy phase diagram respecting the nanoparticle size as an extra variable was calculated by the CALPHAD method. The samples of the Cu–Ni nanoalloys were prepared by the solvothermal synthesis from metal precursors. The samples were characterized by means of dynamic light scattering (DLS), infrared spectroscopy (IR), inductively coupled plasma optical emission spectroscopy (ICP/OES), transmission electron microscopy (TEM, HRTEM), and differential scanning calorimetry (DSC). The nanoparticle size, chemical composition, and Cu–Ni nanoparticles melting temperature depression were obtained. The experimental temperatures of melting of nanoparticles were in good agreement with the theoretical CALPHAD predictions considering surface energy. [Copyright &y& Elsevier]

In this paper, we report the preparation of visible-light active direct Z-scheme Cu2O/WO3 nanocomposite photocatalyst by a solid-state reaction avoiding the otherwise inevitable formation of CuWO4 phase in wet syntheses. Structure, morphology, and thermal and optical properties of prepared WO3 nanoplatelets decorated by Cu2O were investigated by XRD, Raman spectroscopy, SEM/TEM, combined thermogravimetric (TG)/differential scanning calorimetry (DSC) analysis, and UV–VIS spectroscopy. The photocatalytic performance of the prepared samples under UV and visible light was studied through monitoring discoloration of methylene blue under illumination by selected wavelengths, allowing for the distinguishing between the contributions of the two semiconductive components. Experimental results showed that the decoration of WO3 nanoplates by Cu2O nanoparticles led to an improvement in photocatalytic performance, regardless of used LED (Light-Emitting Diode) wavelength, even at low concentrations. By using scavengers selectively blocking reactive species involved in the discoloration reaction, we determined that the Cu2O/WO3 nanocomposite exhibited the characteristics of direct Z-scheme-type photocatalyst. [ABSTRACT FROM AUTHOR]

This study reports the utilization of controlled radical polymerization as a tool for controlling the stimuli-responsive capabilities of graphene oxide (GO) based hybrid systems. Various polymer brushes with controlled molecular weight and narrow molecular weight distribution were grafted from the GO surface by surface-initiated atom transfer radical polymerization (SI-ATRP). The modification of GO with poly(n-butyl methacrylate) (PBMA), poly(glycidyl methacrylate) (PGMA), poly(trimethylsilyloxyethyl methacrylate) (PHEMATMS) and poly(methyl methacrylate) (PMMA) was confirmed by thermogravimetric analysis (TGA) coupled with online Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Various grafting densities of GO-based materials were investigated, and conductivity was elucidated using a four-point probe method. Raman shift and XPS were used to confirm the reduction of surface properties of the GO particles during SI-ATRP. The contact angle measurements indicated the changes in the compatibility of GOs with silicone oil, depending on the structure of the grafted polymer chains. The compatibility of the GOs with poly(dimethylsiloxane) was also investigated using steady shear rheology. The tunability of the electrorheological, as well as the photo-actuation capability, was investigated. It was shown that in addition to the modification of conductivity, the dipole moment of the pendant groups of the grafted polymer chains also plays an important role in the electrorheological (ER) performance. The compatibility of the particles with the polymer matrix, and thus proper particles dispersibility, is the most important factor for the photo-actuation efficiency. The plasticizing effect of the GO-polymer hybrid filler also has a crucial impact on the matrix stiffness and thus the ability to reversibly respond to the external light stimulation. [ABSTRACT FROM AUTHOR]

• Sonochemical Synthesis of MnFe 2 O 4 single-phase spinel ferrite structure. • Impact of sonochemical time and percentage amplitude of ultrasonic power input. • Cation redistribution with increase of sonication time. • Physical characteristics controlled by sonication synthesis condition for specific application. Herein, we report sonochemical synthesis of MnFe 2 O 4 spinel ferrite nanoparticles using UZ SONOPULS HD 2070 Ultrasonic homogenizer (frequency: 20 kHz and power: 70 W). The sonication time and percentage amplitude of ultrasonic power input cause appreciable changes in the structural, cation distribution and physical properties of MnFe 2 O 4 nanoparticles. The average crystallite size of synthesized MnFe 2 O 4 nanoparticles was increased with increase of sonication time and percentage amplitude of ultrasonic power input. The occupational formula by X-ray photoelectron spectroscopy for prepared spinel ferrite nanoparticles was (Mn 0.29 Fe 0.42)[Mn 0.71 Fe 1.58 ]O 4 and (Mn 0.28 Fe 0.54) [Mn 0.72 Fe 1.46 ]O 4 at sonication time 20 min and 80 min, respectively. The value of the saturation magnetization was increased from 1.9 emu/g to 52.5 emu/g with increase of sonication time 20 min to 80 min at constant 50% amplitude of ultrasonic power input, whereas, it was increased from 30.2 emu/g to 59.4 emu/g with increase of the percentage amplitude of ultrasonic power input at constant sonication time 60 min. The highest value of dielectric constant (ε′) was 499 at 1 kHz for nanoparticles at sonication time 20 min, whereas, ac conductivity was 368 × 10−9 S/cm at 1 kHz for spinel ferrite nanoparticles at sonication time 20 min. The demonstrated controllable physical characteristics over sonication time and percentage amplitude of ultrasonic power input are a key step to design spinel ferrite material of desired properties for specific application. The investigation of microwave operating frequency suggest that these prepared spinel ferrite nanoparticles are potential candidate for fabrication of devices at high frequency applications. [ABSTRACT FROM AUTHOR]

Copper sulphide (CuS) powder was prepared in a large-scale by precipitation of Cu2+ cations in aqueous solution by gaseous hydrogen sulphide (H 2 S). XRD and Raman analyses confirmed that precipitated CuS particles possess single crystal phase structure corresponding to mineral covellite with the metallic-like conductivity 3.6 × 103 S cm−1. The powder consisted of non-porous hexagonal nanoplates with specific surface area 19.4 m2 g−1, which can be mainly accounted to {110} crystal plane. In order to shed light into ambiguous reports, covellite photocatalytic effectivity was re-examined. It was revealed, that CuS nanoplates exhibit relatively high adsorption capacity of cationic dye tested, while rate of photocatalytic decomposition of model dye under UV light is negligible if any at all. On the other hand, addition of small amount of H 2 O 2 greatly enhanced the rate of degradation reaction. Furthermore, the reaction proceeds at the same rate even in the dark condition, thus the light is not prerequisite for the dye degradation. From this point of view, the covellite CuS cannot be considered as photocatalyst, but rather as an oxidation catalyst. Moreover, covellite powder exposed to dilute peroxide solution was fully oxidized to Posnjakite Cu 4 (SO 4)(OH) 6 (H 2 O) at room temperature in 24 h. • CuS covellite nanoplates precipitated from Cu2+ ions aq. solution by H 2 S gas. • Catalytic effect of CuS investigated as decay of MV 2B solution absorbance. • Discoloration of the solution proceed at the same rate whether under UV or in dark. • Photocatalytic effect revealed to be only mimicked by adsorption kinetics. • Degradation of MV 2B by H 2 O 2 greatly enhanced in presence of prepared CuS. [ABSTRACT FROM AUTHOR]